Relegation-haunted Bologna dent Inter's Euro hopes
Inter remained fifth with a two-point lead on Parma but the pressure is now on coach Walter Mazzarri, whose side have now failed to win in their last four league outings.
Mauro Icardi scored a brace for the hosts and after just six minutes allayed early fears when he got on the end of Yuto Nagatomo's cross from the left to sweep a volley past Gianluca Curci.
Yet Inter president and owner Erick Thohir, who had called for action from his misfiring side after flying in from Jakarta on Friday, was treated to seeing his side jeered off at half-time after they wasted several chances and saw Bologna come close more than once.
Samir Handanovic had to parry a long-range effort from Lazaros Christodoulopoulos and then Andrea Mantovani sent a glancing header wide of the keeper's far post.
Handanovic then tipped a Cesare Natali header out from under the bar following a free kick, while at the other end Rodrigo Palacio saw his drive curl round Curci's far post.
Halfway through, Inter lost Juan Jesus after the defender clashed with Christodoulopoulos and although he tried to play on after hobbling off Jesus was soon replaced by veteran Walter Samuel.
Barely 10 minutes later Bologna pulled level in spectacular fashion.
Handanovic blocked Christodoulopoulos's effort from close range but could not stop Panagiotis Kone's first-time daisycutter from the rebound, which took a slight deflection off Cristaldo -- credited with the goal -- on its way into the net.
Icardi restored Inter's lead 18 mins into second half, but their joy was short-lived.
Barely 10 minutes later Mantovani's cross from the left caused a defensive mix-up between Cambiasso and Rolando, and Kone pounced to sweep the ball past Handanovic.
Inter were handed a lifeline seven minutes from full-time when Palacio was impeded in the area as he tried to reach Icardi's smart cutback.
The referee pointed to the spot, but Inter's hearts sank when Curci dived to his right to save Milito's somewhat tame effort from the spot.
Inter, defeated once and held twice in their three previous games, were even lucky to escape with a draw with Handanovic saving the hosts' blushes in injury time.
Christodoulopoulos did well to chase the ball down the left and although his centre found Roberto Acquafresca the forward was twice denied by the Inter keeper.
Earlier, veteran striker Luca Toni struck his 16th goal in Serie A this season to help Verona to a 1-0 win in the 'Derby della Scala' away to city rivals Chievo.
Following a challenge with Gennaro Sardo, Toni pounced on a loose ball in the Chievo box to beat Michael Agazzi in the hosts' net for a 65th minute winner.
Verona's 14th win of the campaign moved them up to eighth, and they now sit three points adrift of Inter in fifth spot.